In the past forty years fluorescent lighting has been the illumination of choice in constructing new buildings and spaces for retail, commercial, and office construction. As a general rule, fluorescent lighting has been arranged so that the illumination at floor level is uniform and bright. In an era of inexpensive electricity, this basic design parameter was sensible, especially in view of the fact that the final layout of office desks, retail counters, and the like could not be predicted by the building designer or electrical contractor.
However, in the last decade the increasing cost of electricity has significantly changed the design approach to lighting. It is now much more desirable to reduce the consumption of electicity, not only for the direct reduction of utility costs, but also to reduce air conditioning loads caused by secondary generation of heat in lighting fixtures. As lighting becomes more precious, it is clearly desirable to deliver bright illumination only to those areas where it is required, and to provide low level illumination elsewhere.
The problem for a great many owners and operators of building space is how to reduce electricity consumption for lighting, while providing illumination sufficient for the activities being carried out, without incurring prohibitive costs. One strategy involves removing every other fluorescent tube, and adding either desk lamps or movable track lighting to provide sufficient task illumination. However, the added fixture expense, together with the relative inefficiency of the incandescent lamps in the new fixtures results in little savings. Complete replacement of the existing fluorescent fixtures is another alternative, although the cost of this approach is generally very high.
A recent innovation is retrofit optical reflectors, adapted to be installed in existing fluorescent fixtures. These reflectors are designed to focus the fluorescent illumination on the task areas below the fixtures, so that either some fixtures may be eliminated, or some fluorescent tubes may be removed. These reflectors are generally made of formed sheet metal, much like the fixtures in which they are to be installed. They are not adapted to be altered in the field to focus the light onto specific task areas. Thus, although these prior art devices may increase illumination intensity by 30% directly below the fixtures, they cannot direct the illumination to the locations where it is actually required. Moreover, each of the many fluroescent fixture manufacturers have developed their own fixture designs and dimensions; each type of fixture requires a unique retrofit reflector. In a single building or installation, there may be many differing types of fixtures, each requiring a different type of retrofit reflector.